Matthew 27:28 - Coke's Commentary on the Holy Bible

And they—put on him a scarlet robe— St. Mark says, they cloathed him with purple; but the ancients gave the name of purple to all colours which had any mixture of red in them. This was probably some old purple robe which they put upon him in derision of his claim to the kingdom of Judea, purple being worn by kings and great personages. See Braunius, de Vestit. Sacerd. 50: 1. 100: 14.